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Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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1

Mortimer, N., J. M. Palin, W. J. Dunlap, and F. Hauff. "Extent of the Ross Orogen in Antarctica: new data from DSDP 270 and Iselin Bank." Antarctic Science 23, no. 3 (February 8, 2011): 297–306. http://dx.doi.org/10.1017/s0954102010000969.

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AbstractThe Ross Sea is bordered by the Late Precambrian–Cambrian Ross–Delamerian Orogen of East Antarctica and the more Pacific-ward Ordovician–Silurian Lachlan–Tuhua–Robertson Bay–Swanson Orogen. A calcsilicate gneiss from Deep Sea Drilling Project 270 drill hole in the central Ross Sea, Antarctica, gives a U-Pb titanite age of 437 ± 6 Ma (2σ). This age of high-grade metamorphism is too young for typical Ross Orogen. Based on this age, and on lithology, we propose a provisional correlation with the Early Palaeozoic Lachlan–Tuhua–Robertson Bay–Swanson Orogen, and possibly the Bowers Terrane of northern Victoria Land. A metamorphosed porphyritic rhyolite dredged from the Iselin Bank, northern Ross Sea, gives a U-Pb zircon age of 545 ± 32 Ma (2σ). The U-Pb age, petrochemistry, Ar-Ar K-feldspar dating, and Sr and Nd isotopic ratios indicate a correlation with Late Proterozoic–Cambrian igneous protoliths of the Ross Orogen. If the Iselin Bank rhyolite is not ice-rafted debris, then it represents a further intriguing occurrence of Ross basement found outside the main Ross–Delamerian Orogen.

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2

Reid, Anthony, Marnie Forster, Wolfgang Preiss, Alicia Caruso, Stacey Curtis, Tom Wise, Davood Vasegh, Naina Goswami, and Gordon Lister. "Complex ⁴⁰Ar ∕ ³⁹Ar age spectra from low-grade metamorphic rocks: resolving the input of detrital and metamorphic components in a case study from the Delamerian Orogen." Geochronology 4, no. 2 (July 20, 2022): 471–500. http://dx.doi.org/10.5194/gchron-4-471-2022.

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Abstract. In this study, we provide 40Ar / 39Ar geochronology data from a suite of variably deformed rocks from a region of low-grade metamorphism within the Cambro–Ordovician Delamerian Orogen, South Australia. Low-grade metamorphic rocks such as these can contain both detrital minerals and minerals newly grown or partly recrystallised during diagenesis and metamorphism. Hence, they typically yield complex 40Ar / 39Ar age spectra that can be difficult to interpret. Therefore, we have undertaken furnace step heating 40Ar / 39Ar geochronology to obtain age spectra with many steps to allow for application of the method of asymptotes and limits and recognition of the effects of mixing. The samples analysed range from siltstone and shale to phyllite and contain muscovite or phengite with minor microcline as determined by hyperspectral mineralogical characterisation. Whole rock 40Ar / 39Ar analyses were undertaken in most samples due to their very fine-grained nature. All samples are dominated by radiogenic 40Ar, and contain minimal evidence for atmospheric Ca- or Cl-derived argon. Chloritisation may have resulted in limited recoil, causing 39Ar argon loss in some samples, which is especially evident within the first few percent of gas released. Most of the age data, however, appear to have some geological significance. Viewed with respect to the known depositional ages of the stratigraphic units, the age spectra from this study do appear to record both detrital mineral ages and ages related to the varying influence of either cooling or deformation-induced recrystallisation. The shape of the age spectra and the degree of deformation in the phyllites suggest the younger ages may record recrystallisation of detrital minerals and/or new mica growth during deformation. Given that the younger limit of deformation recorded in the high-metamorphic-grade regions of the Delamerian Orogen is ca. 490 Ma, the ca. 470 to ca. 458 Ma ages obtained in this study suggest deformation in low-grade shear zones within the Delamerian Orogen may have persisted until ca. 20–32 million years after high-temperature ductile deformation in the high-grade regions of the orogen. We suggest that these younger ages for deformation could reflect reactivation of older structures formed both during rift basin formation and during the main peak of the Delamerian orogeny itself. The younger ca. 470 to ca. 458 Ma deformation may have been facilitated by far-field tectonic processes occurring along the eastern paleo-Pacific margin of Gondwana.

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3

Adams, C. J., J. D. Bradshaw, and T. R. Ireland. "Provenance connections between late Neoproterozoic and early Palaeozoic sedimentary basins of the Ross Sea region, Antarctica, south-east Australia and southern Zealandia." Antarctic Science 26, no. 2 (July 18, 2013): 173–82. http://dx.doi.org/10.1017/s0954102013000461.

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AbstractThick successions of turbidites are widespread in the Ross–Delamerian and Lachlan orogens and are now dispersed through Australia, Antarctica and New Zealand. U-Pb detrital zircon age patterns for latest Precambrian, Cambrian and Ordovician metagreywackes show a closely related provenance. The latest Neoproterozoic–early Palaeozoic sedimentary rocks have major components, at c. 525, 550, and 595 Ma, i.e. about 40–80 million years older than deposition. Zircons in these components increase from the Neoproterozoic to Ordovician. Late Mesoproterozoic age components, 1030 and 1070 Ma, probably originate from igneous/metamorphic rocks in the Gondwanaland hinterland whose exact locations are unknown. Although small, the youngest zircon age components are coincident with estimated depositional ages suggesting that they reflect contemporaneous and minor, volcanic sources. Overall, the detrital zircon provenance patterns reflect the development of plutonic/metamorphic complexes of the Ross–Delamerian Orogen in the Transantarctic Mountains and southern Australia that, upon exhumation, supplied sediment to regional scale basin(s) at the Gondwana margin. Tasmanian detrital zircon age patterns differ from those seen in intra-Ross Orogen sandstones of northern Victoria Land and from the oldest metasediments in the Transantarctic Mountains. A comparison with rocks from the latter supports an allochthonous western Tasmania model and amalgamation with Australia in late Cambrian time.

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4

Foden, J. D., M. A. Elburg, S. P. Turner, M. Sandiford, J. O'Callaghan, and S. Mitchell. "Granite production in the Delamerian Orogen, South Australia." Journal of the Geological Society 159, no. 5 (September 2002): 557–75. http://dx.doi.org/10.1144/0016-764901-099.

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5

Foden, John, Marlina A. Elburg, Jon Dougherty‐Page, and Andrew Burtt. "The Timing and Duration of the Delamerian Orogeny: Correlation with the Ross Orogen and Implications for Gondwana Assembly." Journal of Geology 114, no. 2 (March 2006): 189–210. http://dx.doi.org/10.1086/499570.

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6

Shaanan, U., G. Rosenbaum, and F. M. H. Sihombing. "Continuation of the Ross–Delamerian Orogen: insights from eastern Australian detrital-zircon data." Australian Journal of Earth Sciences 65, no. 7-8 (August 21, 2017): 1123–31. http://dx.doi.org/10.1080/08120099.2017.1354916.

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7

Robertson, Kate, David Taylor, Stephan Thiel, and Graham Heinson. "Magnetotelluric evidence for serpentinisation in a Cambrian subduction zone beneath the Delamerian Orogen, southeast Australia." Gondwana Research 28, no. 2 (September 2015): 601–11. http://dx.doi.org/10.1016/j.gr.2014.07.013.

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8

Ireland, T. R., T. Flöttmann, C. M. Fanning, G. M. Gibson, and W. V. Preiss. "Development of the early Paleozoic Pacific margin of Gondwana from detrital-zircon ages across the Delamerian orogen." Geology 26, no. 3 (1998): 243. http://dx.doi.org/10.1130/0091-7613(1998)026<0243:dotepp>2.3.co;2.

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9

Kemp, A. I. S. "Plutonic boninite-like rocks in an anatectic setting: Tectonic implications for the Delamerian orogen in southeastern Australia." Geology 31, no. 4 (2003): 371. http://dx.doi.org/10.1130/0091-7613(2003)031<0371:pblria>2.0.co;2.

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10

Foden, J., M. Sandiford, J. Dougherty-Page, and I. Williams. "Geochemistry and geochronology of the Rathjen Gneiss: Implications for the early tectonic evolution of the Delamerian Orogen." Australian Journal of Earth Sciences 46, no. 3 (June 1999): 377–89. http://dx.doi.org/10.1046/j.1440-0952.1999.00712.x.

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11

Gibson, G. M., D. C. Champion, and T. R. Ireland. "Preservation of a fragmented late Neoproterozoic–earliest Cambrian hyper-extended continental-margin sequence in the Australian Delamerian Orogen." Geological Society, London, Special Publications 413, no. 1 (2015): 269–99. http://dx.doi.org/10.1144/sp413.8.

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12

Johnson, E. L., G. Phillips, and C. M. Allen. "Ediacaran–Cambrian basin evolution in the Koonenberry Belt (eastern Australia): Implications for the geodynamics of the Delamerian Orogen." Gondwana Research 37 (September 2016): 266–84. http://dx.doi.org/10.1016/j.gr.2016.04.010.

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13

Rocchi, S., G. Di Vincenzo, A. Dini, M. Petrelli, and S. Vezzoni. "Time–space focused intrusion of genetically unrelated arc magmas in the early Paleozoic Ross–Delamerian Orogen (Morozumi Range, Antarctica)." Lithos 232 (September 2015): 84–99. http://dx.doi.org/10.1016/j.lithos.2015.06.006.

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14

Gibson, G. M., and D. N. Nihill. "Glenelg River Complex: Western margin of the Lachlan Fold Belt or extension of the Delamerian Orogen into Western Victoria?" Tectonophysics 214, no. 1-4 (November 1992): 69–91. http://dx.doi.org/10.1016/0040-1951(92)90191-8.

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15

Di Vincenzo, Gianfranco, Forrest Horton, and Rosaria Palmeri. "Protracted (~ 30 Ma) eclogite-facies metamorphism in northern Victoria Land (Antarctica): Implications for the geodynamics of the Ross/Delamerian Orogen." Gondwana Research 40 (December 2016): 91–106. http://dx.doi.org/10.1016/j.gr.2016.08.005.

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16

Paulsen, Timothy S., John Encarnación, Anne M. Grunow, Edmund Stump, Mark Pecha, and Victor A. Valencia. "Correlation and Late-Stage Deformation of Liv Group Volcanics in the Ross-Delamerian Orogen, Antarctica, from New U-Pb Ages." Journal of Geology 126, no. 3 (May 2018): 307–23. http://dx.doi.org/10.1086/697036.

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17

Gibson, G. M., and T. R. Ireland. "Extension of Delamerian (Ross) orogen into western New Zealand: Evidence from zircon ages and implications for crustal growth along the Pacific margin of Gondwana." Geology 24, no. 12 (1996): 1087. http://dx.doi.org/10.1130/0091-7613(1996)024<1087:eodroi>2.3.co;2.

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18

Marshak, Stephen, and T. Flöttmann. "Structure and origin of the Fleurieu and Nackara Arcs in the Adelaide fold-thrust belt, South Australia: Salient and recess development in the Delamerian Orogen." Journal of Structural Geology 18, no. 7 (July 1996): 891–908. http://dx.doi.org/10.1016/0191-8141(96)00016-8.

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19

Direen, N. G., D. Brock, and M. Hand. "Geophysical testing of balanced cross-sections of fold–thrust belts with potential field data: an example from the Fleurieu Arc of the Delamerian Orogen, South Australia." Journal of Structural Geology 27, no. 6 (June 2005): 964–84. http://dx.doi.org/10.1016/j.jsg.2005.03.004.

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20

Turner, Simon, Peter Haines, David Foster, Roger Powell, Mike Sandiford, and Robin Offler. "Did the Delamerian Orogeny Start in the Neoproterozoic?" Journal of Geology 117, no. 5 (September 2009): 575–83. http://dx.doi.org/10.1086/600866.

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21

Haines, P. W., and T. Flöttmann. "Delamerian Orogeny and potential foreland sedimentation: A review of age and stratigraphic constraints." Australian Journal of Earth Sciences 45, no. 4 (August 1998): 559–70. http://dx.doi.org/10.1080/08120099808728412.

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22

Moussavi-Harami, R., and D. I. Gravestock. "BURIAL HISTORY OF THE EASTERN OFFICER BASIN, SOUTH AUSTRALIA." APPEA Journal 35, no. 1 (1995): 307. http://dx.doi.org/10.1071/aj94019.

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The intracratonic Officer Basin of central Australia was formed during the Neoproterozoic, approximately 820 m.y. ago. The eastern third of the Officer Basin is in South Australia and contains nine unconformity-bounded sequence sets (super-sequences), from Neoproterozoic to Tertiary in age. Burial history is interpreted from a series of diagrams generated from well data in structurally diverse settings. These enable comparison between the stable shelf and co-existing deep troughs. During the Neoproterozoic, subsidence in the north (Munyarai Trough) was much higher than in either the south (Giles area) or northeast (Manya Trough). This subsidence was related to tectonic as well as sediment loading. During the Cambrian, subsidence was much higher in the northeast and was probably due to tectonic and sediment loading (carbonates over siliciclastics). During the Early Ordovician, subsidence in the north created more accommodation space for the last marine transgression from the northeast. The high subsidence rate of Late Devonian rocks in the Munyarai Trough was probably related to rapid deposition of fine-grained siliciclastic sediments prior to the Alice Springs Orogeny. Rates of subsidence were very low during the Early Permian and Late Jurassic to Early Cretaceous, probably due to sediment loading rather than tectonic sinking. Potential Neoproterozoic source rocks were buried enough to reach initial maturity at the time of the terminal Proterozoic Petermann Ranges Orogeny. Early Cambrian potential source rocks in the Manya Trough were initially mature prior to the Delamerian Orogeny (Middle Cambrian) and fully mature on the Murnaroo Platform at the culmination of the Alice Springs Orogeny (Devonian).

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23

Yi, Sang-Bong, Mi Lee, Jong Lee, and Hwayoung Kim. "Timing and Metamorphic Evolution of the Ross Orogeny in and around the Mountaineer Range, Northern Victoria Land, Antarctica." Minerals 10, no. 10 (October 13, 2020): 908. http://dx.doi.org/10.3390/min10100908.

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The Ross(–Delamerian) Orogeny significantly impacted the formation of the tectonic structure of the Pacific Gondwana margin during the early Paleozoic era. Northern Victoria Land (NVL) in Antarctica preserves the aspect of the Ross Orogeny that led to the union of the Wilson (WT)–Bowers (BT)–Robertson Bay Terrane. The aspect of the Ross Orogeny in the NVL is characterized by subduction of oceanic domains toward the continental margin (continental arc) and the accretion of the associated marine–continental substances from 530–480 Ma. In the Mountaineer Range in NVL, the Ross Orogeny strain zone is identified at the WT/BT boundary regions. In these areas, fold and thrust shear zones are observed and aspects of them can be seen at Mt. Murchison, the Descent Unit and the Black Spider Greenschist zone. The Dessent Unit corresponds to a tectonic slice sheared between the WT and BT. The metamorphic evolution phase of the Dessent Unit is summarized in the peak pressure (M1), peak temperature (M2) and retrograde (M3). The sensitive high-resolution ion microprobe (SHRIMP) zircon U–Pb ages of 514.6 ± 2.0 Ma and 499.2 ± 3.4 Ma obtained from the Dessent Unit amphibolite are comparable to the M1 and M2 stages, respectively. The Dessent Unit underwent intermediate pressure (P)/temperature (T)-type metamorphism characterized by 10.0–10.5 kbar/~600 °C (M1) and ~7 kbar/~700 °C (M2) followed by 4.0–4.5 kbar/~450 °C (M3). Mafic to intermediate magmatism (497–501 Ma) within the WT/BT boundary region may have given rise to the M2 stage of the Dessent Unit, and this magmatism is synchronous with the migmatization period of Mt. Murchison (498.3 ± 3.4 Ma). This indicates that a continuous process of fold-shearing–magmatic intrusion–partial melting, which is typically associated with a continental arc orogeny, occurred before and after c. 500 Ma in the Mountaineer Range. During the Ross Orogeny, the Dessent unit was initially subducted underneath the WT at depth (10.0–10.5 kbar, ~35 km) and then thrust into the shallow (~7 kbar, ~23 km), hot (≥700 °C) magmatic arc docking with the Mt. Murchison terrain, where migmatization prevailed.

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24

Foden, John, Marlina Elburg, Simon Turner, Chris Clark, Morgan L. Blades, Grant Cox, Alan S. Collins, Keryn Wolff, and Christian George. "Cambro-Ordovician magmatism in the Delamerian orogeny: Implications for tectonic development of the southern Gondwanan margin." Gondwana Research 81 (May 2020): 490–521. http://dx.doi.org/10.1016/j.gr.2019.12.006.

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25

Robertson, K. E., G. S. Heinson, D. H. Taylor, and S. Thiel. "The lithospheric transition between the Delamerian and Lachlan orogens in western Victoria: new insights from 3D magnetotelluric imaging." Australian Journal of Earth Sciences 64, no. 3 (March 13, 2017): 385–99. http://dx.doi.org/10.1080/08120099.2017.1292953.

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26

Rutherford, Lachlan, Martin Hand, and Joanna Mawby. "Delamerian-aged metamorphism in the southern Curnamona Province, Australia: implications for the evolution of the Mesoproterozoic Olarian Orogeny." Terra Nova 18, no. 2 (March 21, 2006): 138–46. http://dx.doi.org/10.1111/j.1365-3121.2006.00673.x.

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27

Flöottmann, Thomas, George M. Gibson, and Georg Kleinschmidt. "Structural continuity of the Ross and Delamerian orogens of Antarctica and Australia along the margin of the paleo-Pacific." Geology 21, no. 4 (1993): 319. http://dx.doi.org/10.1130/0091-7613(1993)021<0319:scotra>2.3.co;2.

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28

Withnall, I. W., S. D. Golding, I. D. Rees, and S. K. Dobos. "K—Ar dating of the Anakie Metamorphic Group: Evidence for an extension of the Delamerian Orogeny into central Queensland." Australian Journal of Earth Sciences 43, no. 5 (October 1996): 567–72. http://dx.doi.org/10.1080/08120099608728277.

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29

Rawlinson, N., B. L. N. Kennett, E. Vanacore, R. A. Glen, and S. Fishwick. "The structure of the upper mantle beneath the Delamerian and Lachlan orogens from simultaneous inversion of multiple teleseismic datasets." Gondwana Research 19, no. 3 (April 2011): 788–99. http://dx.doi.org/10.1016/j.gr.2010.11.001.

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30

Miller, J. McL, D. Phillips, C. J. L. Wilson, and L. J. Dugdale. "Evolution of a reworked orogenic zone: The boundary between the delamerian and lachlan fold belts, southeastern Australia *." Australian Journal of Earth Sciences 52, no. 6 (December 2005): 921–40. http://dx.doi.org/10.1080/08120090500304265.

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31

Boger, S. D., and J. McL Miller. "Terminal suturing of Gondwana and the onset of the Ross–Delamerian Orogeny: the cause and effect of an Early Cambrian reconfiguration of plate motions." Earth and Planetary Science Letters 219, no. 1-2 (February 2004): 35–48. http://dx.doi.org/10.1016/s0012-821x(03)00692-7.

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32

Korsch, R. J., T. J. Barton, D. R. Gray, A. J. Owen, and D. A. Foster. "Geological interpretation of a deep seismic‐reflection transect across the boundary between the Delamerian and Lachlan Orogens, in the vicinity of the Grampians, western Victoria." Australian Journal of Earth Sciences 49, no. 6 (December 2002): 1057–75. http://dx.doi.org/10.1046/j.1440-0952.2002.00963.x.

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33

Cayley, R. A. "Exotic crustal block accretion to the eastern Gondwanaland margin in the Late Cambrian–Tasmania, the Selwyn Block, and implications for the Cambrian–Silurian evolution of the Ross, Delamerian, and Lachlan orogens." Gondwana Research 19, no. 3 (April 2011): 628–49. http://dx.doi.org/10.1016/j.gr.2010.11.013.

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34

Rai, Shashi Ranjan, Himanshu K. Sachan, Christopher J. Spencer, Aditya Kharya, Saurabh Singhal, Arun Kumar Ojha, Pallavi Chattopadhaya, and Pitambar Pati. "Zircon geochronology and Hf isotopic study from the Leo Pargil Dome, India: implications for the palaeogeographic reconstruction and tectonic evolution of a Himalayan gneiss dome." Geological Magazine, July 11, 2022, 1–18. http://dx.doi.org/10.1017/s0016756822000449.

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Abstract U–Pb geochronology, Hf isotopes and trace-element chemistry of zircon grains from migmatite of the upper Sutlej valley (Leo Pargil), Northwest Himalaya, reveal a protracted geological evolution and constrain anatexis and tectonothermal processes in response to Himalayan orogenesis. U–Pb geochronology and ϵHf record separate clusters of ages on the concordia plots in the migmatite (1050–950 Ma, 850–790 Ma and 650–500 Ma). The 1050–950 Ma zircon population supports a provenance from magmatic units related to the assembly of Rodinia. A minor amount of Palaeoproterozoic grains were likely derived from the Indian craton. The potential source rock of the 930–800 Ma detrital zircons may be granitoid present in Greater Himalayan rocks themselves and the Aravalli Range, which has 870–800 Ma granitic rocks. The arc-type basement within the Himalayan–Tibet orogen recorded (900–600 Ma) igneous activity, which may depict a northeasterly extension of juvenile terranes in the Arabian–Nubian Shield. The granitoid of 800 Ma may be a potential source for 790 Ma detrital zircons owing to scatter in 206/238 dates. The 650–500 Ma zircon population suggests their derivation from the East African Orogen and Ross–Delamerian Orogen of Gondwana. The Cambrian–Ordovician magmatism during the Bhimphedian Orogeny and observed late Neoproterozoic to Ordovician detrital zircons have been derived to some extent from Greater Himalayan magmatic sources. We found no detrital zircon grains that cannot be explained as coming from local sources. One sample yielded a discordia lower intercept age of 15.6 ± 2.2 Ma, the age of melt crystallization.

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35

Craddock, John P., Timothy Paulsen, Renata de Silva Schmitt, Stephen T. Johnston, Paul M. Myrow, and Nigel C. Hughes. "Amalgamation of Gondwana: Calcite Twinning and Finite Strains from the early to late Paleozoic Buzios, Ross, Kurgiakh, and Gondwanide Orogens." Geological Society, London, Special Publications 531, no. 1 (November 3, 2022). http://dx.doi.org/10.1144/sp531-2022-165.

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Abstract Oriented carbonate (calcite twinning strains; n=78 with 2414 twin measurements) and quartzites (finite strains, n=15) were collected around Gondwana to study the deformational history associated with the amalgamation of the supercontinent. The Buzios orogen (545-500 Ma), within interior Gondwana, records the high-grade collisional orogen between São Francisco craton (Brazil) and Congo-Angola craton (Angola-Namibia) and twinning strains in calcsilicates record a SE-NW shortening fabric parallel to thrust transport. Along Gondwana's southern margin, the Saldanian-Ross-Delamerian orogen (590-480 Ma) is marked by a regional unconformity that cuts into deformed Neoproterozoic-Ordovician sedimentary rocks and associated intrusions. Cambrian carbonate is preserved in the central part of the southern Gondwana margin, namely in the Kango inlier of the Cape fold belt and the Ellsworth, Pensacola and Transantarctic Mountains. Paleozoic carbonate is not preserved in the Ventana Mountains, Argentina; Islas Malvinas/Falkland Islands or Tasmania. Twinning strains in these Cambrian carbonate strata and synorogenic veins record a complex, overprinted deformation history with no stable foreland strain reference. The Kurgiakh orogen (490 Ma) along Gondwana's northern margin is also defined by a regional Ordovician unconformity throughout the Himalaya; these rocks record a mix of layer-parallel and layer-normal twinning strains with a likely Himalayan (40 Ma) strain overprint and no autochthonous foreland strain site. Conversely, the Gondwanide orogen (250 Ma) along Gondwana's southern margin has three foreland (autochthonous) sites for comparison with 59 allochthonous thrust belt strain analyses. From west to east: finite strains from Devonian quartzite preserve a layer-parallel shortening (LPS) strain rotated clockwise in the Ventana Mountains, Argentina; the frontal (calcite twins) and internal (quartzite strains) samples in the Cape belt preserve a LPS fabric that is rotated clockwise from the autochthonous N-S horizontal shortening in the foreland strain site; Falkland Devonian quartzite shows the same clockwise rotation of the LPS fabric; Permian limestone and veins in Tasmania record a thrust transport-parallel LPS fabric. Early amalgamation of Gondwana (Ordovician) is preserved by local layer-parallel and layer-normal strain without evidence of far-field deformation whereas the Gondwanide orogen (Permian) is dominated by layer-parallel shortening, locally rotated by dextral shear along the margin, that propagated across the supercontinent.

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36

"Development of the early Paleozoic Pacific margin of Gondwana from detrital-zircon ages across the Delamerian orogen." Journal of African Earth Sciences 27, no. 3-4 (October 1998): XII. http://dx.doi.org/10.1016/s0899-5362(98)90636-4.

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37

Turner, Simon, Trevor Ireland, John Foden, Elena Belousova, Gerhard Wörner, and Jelte Keeman. "A comparison of granite genesis in the Adelaide Fold Belt and Glenelg River Complex using U-Pb, Hf and O isotopes in zircon." Journal of Petrology, October 11, 2022. http://dx.doi.org/10.1093/petrology/egac102.

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Abstract We present new U-Pb ages and Hf and O isotope data for zircon from I-, S- and A-type granites from both the western and eastern edges of the Delamerian Orogen in southeastern Australia. The I-type Tanunda Creek Gneiss contains zircon populations of 507 ± 4 Ma and 492 ± 6 Ma inferred to reflect igneous and metamorphic ages, respectively. The I-type Palmer Granite yielded an age of 509 ± 3 Ma and the Port Elliot S-type Granite has a magmatic age of 508 ± 7 Ma. Inherited zircon in these granites range from 1092 to 3343 Ma, probably derived from assimilation of Adelaide Group sediments. The Murray Bridge A-type Granite is 490 ± 2 Ma in age and lacks inherited zircon. In the Glenelg River Complex, a S-type migmatite from near Harrow contains a complex zircon population. It is most likely ~ 500 Ma in age and has inherited zircon of 550-700, 1000-1100 and 2437 Ma, hence matching those from the Kanmantoo Group. From this and detrital zircons ages we infer that only the Kanmantoo Group extends across the Murray Basin into the Glenelg River Complex. The Wando Tonalite and Loftus Creek I-type granites yielded ages of 501 ± 2 Ma and 486 ± 3 Ma, respectively. Zircon from the Dergholm Granite has suffered Pb loss and the best age estimate for this granite is 488 ± 5 Ma. Combining all the granite data together, εHft and δ18O in the magmatic zircon range from 5.6 to -10.3 and from 5.8 to 8.1, respectively, and are well correlated. The zircon indicate the same temporal and compositional evolution of granitic petrogenesis across ~ 300 km of strike, reaffirming the notion that these terranes form part of the same orogen. Westward-directed subduction caused orogenic thickening, heating and increasing amounts of crustal contribution. This was followed by convective thinning of the thickened mantle lithosphere and a return to more primitive magmas lacking significant crustal contributions. It contrasts significantly with inferred granite petrogenesis and tectonic style in the younger Lachlan and New England Fold Belts further east that were not built upon extended cratonic lithosphere.

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"Extension of Delamerian (Ross) Orogen into western New Zealand: evidence from zircon ages and implications for crustal growth along the Pacific margin of Gondwana." Journal of African Earth Sciences 26, no. 2 (February 1998): VII. http://dx.doi.org/10.1016/s0899-5362(97)83537-3.

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